Oil Pressure gauge is almost useless

[dpinvidic]

I saw a thread from another member who asked how much the oil pressure should change between idle and driving.

So I brought up the reading on the EVIC. The gauge is almost worthless and could be replaced by an idiot light.

While driving, the pres. Is 53 PSI, and the needle is right on top of the middle mark.
At Idle, the pres. Is 33 psi, and the needle drops, but is still touching the middle mark.

I am curious how much it has to drop before the needle moves a significant amount.

The readings are not anywhere near linear. Maybe they program the gauge to work that way so people don’t get concerned when the needle
Drops from ½ to 3/8 of the dial then they come to idle.

See photos.

Dan

 

[Diller]

Most cars/trucks have a dummy gauge for oil pressure for the reason you stated. Cold oil pressure is much much higher than when warm and idling. If people saw the oil pressure drop from 55-70 down to 30psi, some may get alarmed. I don't know about the Ram, but on other cars I have had the gauge doesn't move unless it gets dangerously low (like below 10psi)

 

[ramenthusiast]

Most cars/trucks have a dummy gauge for oil pressure for the reason you stated. Cold oil pressure is much much higher than when warm and idling. If people saw the oil pressure drop from 55-70 down to 30psi, some may get alarmed. I don't know about the Ram, but on other cars I have had the gauge doesn't move unless it gets dangerously low (like below 10psi)

^^^This. The people smart enough to know how a real oil pressure gauge operates are far outnumbered by those who don't. To prevent needless concern (and warranty trips to the dealer) most of the gauges are designed to represent just an acceptable range of operation and function little better than idiot lights. That's why there are no actual numbers on these gauges, just indicator bars. If you saw your voltmeter go from 13.6v on the highway to 12v or less at idle with the lights and A/C on and you didn't know that was normal you might be alarmed. Manufacturers prefer to treat us all like dummies and assume we don't know any better. Problem is, more often than not they are right.